Device and method to calibrate parallax optical element

ABSTRACT

Provided is an electronic device including a display to output an image, a parallax optical element configured to provide light corresponding to the image to a plurality of viewpoints, an input interface configured to receive an input to calibrate the parallax optical element by a user who observes a pattern image from a reference viewpoint among the plurality of viewpoints, and a processor configured to output the pattern image generated by rendering a calibration pattern toward the reference viewpoint, adjust at least one of a pitch parameter, a slanted angle parameter, and a position offset parameter of the parallax optical element based on the input, and output, by the display, the pattern image adjusted by re-rendering the calibration pattern based on an adjusted parameter.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Korean Patent Application No.10-2021-0099801, filed on Jul. 29, 2021, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein byreference in its entirety.

BACKGROUND 1. Field

Example embodiments of the present disclosure relate to methods andapparatuses directed to calibration of a parallax optical element.

2. Description of Related Art

The most dominant factor among factors for recognizing a stereoscopicimage is a difference between images viewed by both eyes of a user. Ascheme of presenting different images to both eyes of a user may includea stereoscopic scheme of filtering images using, for example,polarization-based division, time division, or wavelength division ofvarying a wavelength of a primary color, and an autostereoscopic schemeof presenting each image to be viewed from a predetermined viewpointusing a three-dimensional (3D) conversion device, such as, for example,a parallax barrier, a lenticular lens, or a directional backlight unit.

Using the autostereoscopic scheme, the inconvenience of wearing glassesmay be reduced. In the autostereoscopic scheme, a 3D image may beaccurately projected toward both eyes of a user to prevent crosstalk ofthe 3D image. However, an image quality may be degraded when an errordifferent from a design value occurs in a production process or aninstallation process of a 3D display device and a 3D conversion device.

SUMMARY

One or more example embodiments may address at least the above problemsand/or disadvantages and other disadvantages not described above. Also,the example embodiments are not required to overcome the disadvantagesdescribed above, and an example embodiment may not overcome any of theproblems described above.

According to an aspect of an example embodiment, there is provided anelectronic device including a display to output an image, a parallaxoptical element configured to provide light corresponding to the imageto a plurality of viewpoints, an input interface configured to receivean input to calibrate the parallax optical element by a user whoobserves a pattern image from a reference viewpoint among the pluralityof viewpoints, and a processor configured to output the pattern imagegenerated by rendering a calibration pattern toward the referenceviewpoint, adjust at least one of a pitch parameter, a slanted angleparameter, and a position offset parameter of the parallax opticalelement based on the input, and output, by the display, the patternimage adjusted by re-rendering the calibration pattern based on anadjusted parameter.

The processor may be further configured to rotate a patterncorresponding to a first pattern image in a counterclockwise directionfrom a direction in which the user observes the pattern, based on anincrease in a value of the pitch parameter among parameters of theparallax optical element based on the input, and rotate the patterncorresponding to the first pattern image in a clockwise direction fromthe direction in which the user observes the pattern, based on adecrease in the value of the pitch parameter among the parameters of theparallax optical element based on the input.

The processor may be further configured to rotate a patterncorresponding to a second pattern image in a clockwise direction from adirection in which the user observes the pattern, based on an increasein a value of the slanted angle parameter among parameters of theparallax optical element based on the input, and rotate the patterncorresponding to the second pattern image in a counterclockwisedirection from the direction in which the user observes the pattern,based on a decrease in the value of the slanted angle parameter amongthe parameters of the parallax optical element based on the input.

The processor may be further configured to move a pattern correspondingto a third pattern image in one direction from a direction in which theuser observes the pattern, based on an increase in a value of theposition offset parameter among parameters of the parallax opticalelement based on the input, and move the pattern corresponding to thethird pattern image in an opposite direction to the one direction fromthe direction in which the user observes the pattern, based on adecrease in the value of the position offset parameter among theparameters of the parallax optical element based on the input.

The input interface may include at least one of a touch panel, a touchscreen, a dial, a jog dial, a shuttle dial, a click wheel, a button, aslider bar, and a control lever.

The processor may be further configured to map adjustment of at leastone of the pitch parameter and the slanted angle parameter to an inputdevice configured to detect a rotation control in the input interface,and map adjustment of the position offset parameter to the input devicefurther configured to detect a linear control in the input interface.

The input interface may be configured to detect a rotation control inputby the user, and the processor may be further configured to adjust atleast one of the pitch parameter and the slanted angle parameter amongparameters of the parallax optical element, based on the rotationcontrol input by the user being detected by the input interface duringcalibration of the parallax optical element.

The processor may be further configured to rotate a first calibrationpattern corresponding to a first pattern image corresponding to thepitch parameter in a counterclockwise direction, based on acounterclockwise rotation control being detected by the input interfacewhile the first pattern image is being provided, and rotate the firstcalibration pattern corresponding to the first pattern image in aclockwise direction, based on a clockwise rotation control beingdetected by the input interface while the first pattern image is beingprovided.

The processor may be further configured to increase a value of the pitchparameter, based on the counterclockwise rotation control being detectedby the input interface while the first pattern image is being provided,and reduce the value of the pitch parameter, based on the clockwiserotation control being detected by the input interface while the firstpattern image is being provided.

The processor may be further configured to rotate a second calibrationpattern corresponding to a second pattern image corresponding to theslanted angle parameter in a clockwise direction, based on a clockwiserotation control being detected by the input interface while the secondpattern image is being provided, and rotate the second calibrationpattern corresponding to the second pattern image in a counterclockwisedirection, based on a counterclockwise rotation control being detectedby the input interface while the second pattern image is being provided.

The processor may be further configured to increase a value of theslanted angle parameter, based on the clockwise rotation control beingdetected by the input interface while the second pattern image is beingprovided, and reduce the value of the slanted angle parameter, based onthe counterclockwise rotation control being detected by the inputinterface while the second pattern image is being provided.

The processor may be further configured to move a third calibrationpattern corresponding to a third pattern image corresponding to theposition offset parameter in a first direction, based on a linearcontrol in the first direction being detected by the input interfacewhile the third pattern image is being provided, and move the thirdcalibration pattern corresponding to the third pattern image in a seconddirection that is opposite to the first direction, based on a linearcontrol in the second direction to the first direction being detected bythe input interface while the third pattern image is being provided.

The processor may be further configured to increase a value of theposition offset parameter, based on a linear control in a firstdirection being detected by the input interface while a third patternimage corresponding to the position offset parameter is being provided,and reduce the value of the position offset parameter based on a linearcontrol in a second direction opposite to the first direction beingdetected by the input interface while the third pattern image is beingprovided.

The input interface may include a touch screen, and the processor may befurther configured to output, to the touch screen, a first graphicrepresentation configured to guide a rotation control during calibrationof at least one of the pitch parameter and the slanted angle parameter,adjust at least one of the pitch parameter and the slanted angleparameter, based on a movement of a touch point along at least partiallycircular trajectory from a point on the touch screen being detectedcorresponding to the first graphic representation, output, to the touchscreen, a second graphic representation configured to guide a linearcontrol during calibration of the position offset parameter, and adjustthe position offset parameter, based on a linear movement of a touchpoint from one point on the touch screen to another point being detectedcorresponding to the second graphic representation.

The processor may be further configured to store parameters of theparallax optical element that are personalized to the user, based on acalibration completion input being received from the user, and render acontent image based on the personalized parameters and output thecontent image to the display.

The processor may be further configured to provide the user with atleast one of a first pattern image corresponding to the pitch parameter,a second pattern image corresponding to the slanted angle parameter, anda third pattern image corresponding to the position offset parameter.

The processor may be further configured to provide the second patternimage to the user, based on adjustment of the pitch parameter byproviding the first pattern image being completed, and provide the thirdpattern image to the user, based on adjustment of the slanted angleparameter by providing the second pattern image being completed.

The display may be included in a head-up display (HUD) mounted on avehicle, wherein the vehicle is one of a motorcycle, an automobile, atrain, a watercraft, an aircraft, and a spacecraft.

According to another aspect of an example embodiment, there is provideda method implemented by a processor, the method including providinglight corresponding to a pattern image to a reference viewpoint througha parallax optical element, the pattern image being generated byrendering a calibration pattern and output from a display, receiving aninput to calibrate parameters of the parallax optical element by a userwho observes the pattern image from the reference viewpoint, adjustingat least one of a pitch parameter, a slanted angle parameter, and aposition offset parameter of the parallax optical element, based on theinput, and outputting the pattern image adjusted by re-rendering thecalibration pattern based on an adjusted parameter, by the display.

A non-transitory computer-readable storage medium storing instructionsthat, when executed by the processor, may cause the processor to performthe method.

According to another aspect of an example embodiment, there is providedan electronic device including a head-up display (HUD) configured tooutput an image, a parallax optical element configured to provide lightcorresponding to the image to a plurality of viewpoints, an inputinterface configured to receive an input to calibrate the parallaxoptical element by a user who observes a pattern image from a referenceviewpoint among the plurality of viewpoints, and a processor configuredto output the pattern image generated by rendering a calibration patterntoward the reference viewpoint, adjust at least one of a pitchparameter, a slanted angle parameter, and a position offset parameter ofthe parallax optical element based on the input, and output, by the HUD,the pattern image adjusted by re-rendering the calibration pattern basedon an adjusted parameter, wherein the input interface includes at leastone of a touch panel, a touch screen, a dial, a jog dial, a shuttledial, a click wheel, a button, a slider bar, and a control lever.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or other aspects will be more apparent by describingexample embodiments, taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 illustrates an electronic device that performs calibration of aparallax optical element according to an example embodiment;

FIG. 2 illustrates an example in which an electronic device includes ahead-up display (HUD) according to an example embodiment;

FIG. 3 is a block diagram of an electronic device according to anexample embodiment;

FIG. 4 illustrates source images, a pattern image, and observed imagesfor calibration of a parallax optical element according to an exampleembodiment;

FIG. 5 illustrates a source image and an observed image according to anexample embodiment;

FIG. 6 illustrates parameters of a parallax optical element according toan example embodiment;

FIGS. 7, 8, and 9 illustrate examples of a change in a pattern imagebased on adjustment of parameters according to an example embodiment;

FIG. 10 illustrates parameter adjustment using a slider bar according toan example embodiment;

FIG. 11 illustrates parameter adjustment using a touch interfaceaccording to an example embodiment;

FIG. 12 illustrates parameter adjustment using a dial interfaceaccording to an example embodiment;

FIG. 13 illustrates a calibration result according to an exampleembodiment; and

FIG. 14 is a flowchart illustrating a calibration method according to anexample embodiment.

DETAILED DESCRIPTION

The following detailed structural or functional description of exampleembodiments is provided as an example only and various alterations andmodifications may be made to the example embodiments. Here, the exampleembodiments are not construed as limited to the disclosure and should beunderstood to include all changes, equivalents, and replacements withinthe idea and the technical scope of the disclosure.

Terms, such as first, second, and the like, may be used herein todescribe various components. Each of these terminologies is not used todefine an essence, order or sequence of a corresponding component butused merely to distinguish the corresponding component from othercomponent(s). For example, a first component may be referred to as asecond component, and similarly the second component may also bereferred to as the first component.

It should be noted that if it is described that one component is“connected”, “coupled”, or “joined” to another component, a thirdcomponent may be “connected”, “coupled”, and “joined” between the firstand second components, although the first component may be directlyconnected, coupled, or joined to the second component.

The singular forms “a”, “an”, and “the” are intended to include theplural forms as well, unless the context clearly indicates otherwise. Itwill be further understood that the terms “comprises/including” and/or“includes/including” when used herein, specify the presence of statedfeatures, integers, steps, operations, elements, and/or components, butdo not preclude the presence or addition of one or more other features,integers, steps, operations, elements, components and/or groups thereof.

Unless otherwise defined, all terms, including technical and scientificterms, used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure pertains. Terms,such as those defined in commonly used dictionaries, are to beinterpreted as having a meaning that is consistent with their meaning inthe context of the relevant art, and are not to be interpreted in anidealized or overly formal sense unless expressly so defined herein.

Hereinafter, example embodiments will be described in detail withreference to the accompanying drawings. When describing the exampleembodiments with reference to the accompanying drawings, like referencenumerals refer to like constituent elements and a repeated descriptionrelated thereto will be omitted.

FIG. 1 illustrates an electronic device that performs calibration of aparallax optical element according to an example embodiment.

An electronic device 100 according to an example embodiment may providea stereoscopic image to a user. For example, the electronic device 100may provide images having binocular disparity to both eyes of a user.Images having binocular disparity may include, for example, a firstimage provided to a left eye of a user and a second image provided to aright eye of the user. Pixels corresponding to the same object and/orthe same point in the first image and the second image may be spacedapart by a disparity according to a depth (e.g., a distance to acorresponding object defined and/or set to be recognized by a user) of acorresponding object and/or a corresponding point. However, forconvenience of description, an example in which a stereoscopic image isprovided to a left eye and a right eye of a user at a first viewpointand a second viewpoint that respectively correspond to the left eye andthe right eye of the user is described above, however, the exampleembodiments are not limited thereto. Depending on example embodiments,images may be designed to be provided to two or more viewpoints, or astereoscopic image may be designed to be provided to two or more users.For example, the electronic device 100 may provide an image pair havingbinocular disparity for each pixel to a first viewpoint corresponding toa left eye of a first user and a second viewpoint corresponding to aright eye of the first user. In addition, the electronic device 100 mayprovide an image pair having binocular disparity for each pixel to athird viewpoint corresponding to a left eye of a second user and afourth viewpoint corresponding to a right eye of the second user.

The electronic device 100 may output an image through a display panel,and a parallax optical element of the electronic device 100 may beconfigured to direct light corresponding to the output image to aplurality of viewpoints. Due to an error and/or tolerance in amanufacturing process, a portion of an image that needs to be providedto a left eye and/or a right eye of a user may be observed by theopposite eye, if fine tuning through calibration is not performed. Sucha phenomenon in which an image that needs to be observed from oneviewpoint is observed from another viewpoint may be referred to ascrosstalk. A left eye image may need to be observed from a viewpointcorresponding to a left eye of a user and a right eye image may need tobe observed from a viewpoint corresponding to a right eye of the user,so that the user may accurately recognize a sense of depth and may viewa clear image.

The electronic device 100 may perform calibration to reduce and/oreliminate the above-described crosstalk. The electronic device 100 mayprovide a user with a calibration pattern 110 corresponding to a patternimage for calibration. The electronic device 100 may receive an input129 for calibration from a user who observes the calibration pattern 110corresponding to the pattern image. When the input 129 for calibrationis received, the electronic device 100 may adjust a parameter of theparallax optical element to correspond to the input 129. The electronicdevice 100 may change the calibration pattern 110 corresponding to thepattern image according to the adjusted parameter. The user mayrepeatedly provide an input to control the calibration until thecalibration pattern 110 corresponding to the pattern image is alignedwith a reference line (e.g., a vertical line and/or a horizontal line).The electronic device 100 may provide a convenient input interface 120for manipulation for calibration. For example, in FIG. 1 , when a touchscreen of the electronic device 100 displays a slider bar and when theelectronic device 100 detects the input 129 (e.g., an input tohorizontally move a slider bar object) on the slider bar, the parameterof the parallax optical element may be adjusted.

For example, as shown in FIG. 1 , the electronic device 100 may bemounted on a vehicle may provide a content image and/or a pattern imageto a user by projecting the content image and/or the pattern imagethrough a windshield of the vehicle. However, embodiments are notlimited thereto. A head-up display (HUD) using a windshield will bedescribed below with reference to FIG. 2 .

FIG. 2 illustrates an electronic device including a head-up display(HUD) according to an example embodiment.

A calibration system 200 may be a system that provides a user 290 withcalibration of a parallax optical element, and may be, for example, adevice including an electronic device 210 (e.g., the electronic device100 of FIG. 1 ).

The electronic device 210 may include a processor 212 and a HUD 213. Theelectronic device 210 may also include an eye detector.

The processor 212 may provide a pattern image to the user 290 byoutputting a rendered pattern image through the HUD 213. The processor212 may re-render the pattern image based on a parameter adjustedaccording to an input of a user during calibration and may provide there-rendered pattern image. After the calibration is completed, theprocessor 212 may render a content image using a fixed parameter and mayprovide the content image to the user. The content image may be, forexample, information including content associated with driving, andinformation (hereinafter, driving information) associated with drivingof a vehicle may include, for example, route guidance information anddriving related information.

The HUD 213 may visualize a stereoscopic image in a visible region ofthe user 290 that is positioned in front of the user 290. For example,the HUD 213 may visualize a pattern image on a window (e.g., awindshield of a vehicle) disposed in front of the user 290. The HUD 213may form a virtual projection plane 250. The projection plane 250 may bea plane on which a virtual image including a pattern generated by theHUD 213 is displayed. The user 290 may recognize the virtual image asbeing disposed on the projection plane 250. For example, due to anoptical system by a windshield of a vehicle and of the HUD 213, a usermay view an image 230 that represents a calibration pattern (e.g., anobserved pattern) of a different type from an intended calibrationpattern. The image 230 may represent a form in which the calibrationpattern is further blurred in comparison to the intended calibrationpattern or in which a gradation is added.

The HUD 213 may also visualize a content image having a depth on theprojection plane 250. For example, the processor 212 may provide theuser 290 with a content image including a left image and a right imagewith binocular disparity corresponding to a depth at which an object maybe visualized, using the HUD 213. The HUD 213 may visualize contenthaving a corresponding depth in a virtual region 260 on the projectionplane 250. In an example, the processor 212 may render content to be athree dimensional (3D) graphic representation based on an optical systemof the HUD 213. The 3D graphic representation may express a stereoscopicgraphic representation having a depth. The HUD 213 may form a contentimage including a left image and a right image on the projection plane250 based on a depth of the content. Through the projection plane 250,the left image may be provided to the left eye of the user 290 and theright image may be provided to the right eye of the user 290. Forexample, one virtual image may be formed on the projection plane 250,but may be separated into light corresponding to the left image andlight corresponding to the right image by the optical system of the HUD213 and the windshield, so that the left image and the right image maybe directed to the left eye and the right eye of the user 290,respectively. Thus, the user 290 may recognize a sense of depth ofstereoscopically rendered content.

The HUD 213 may include, for example, a picture generator 214, a foldmirror 215, and a concave mirror 216. The picture generator 214 mayinclude a display (e.g., a display panel) and a parallax opticalelement. The parallax optical element may include, for example, alenticular lens and a parallax barrier. However, the configuration ofthe HUD 213 is not limited thereto, and various components forming theprojection plane 250 on which a virtual image is formed throughprojection toward a glass window disposed in front of the user 290 maybe included depending on a design.

Although an example in which the electronic device 210 is mounted on avehicle is mainly described herein, embodiments are not limited thereto.For example, the electronic device 210 may be applied to technology thatcombines information of a real world and information of a virtual world,such as, for example, augmented reality (AR) glasses or mixed reality(MR), and may also be applied to a vehicle, such as, for example, amotorcycle, an airplane, or a train.

In an example, the electronic device 210 may continue to express a depthby adjusting a depth of content, without changing a position of theprojection plane 250 formed by the HUD 213. Since the position of theprojection plane 250 does not need to be changed, the electronic device210 may not require a physical control for components included in theHUD 213.

FIG. 3 is a block diagram of an electronic device according to anexample embodiment.

The electronic device 300 according to an example embodiment may includea display 310, a parallax optical element 320, an input receiver orinterface 330, a processor 340, and a memory 350. The electronic device300 may also include an eye detector.

The display 310 may visualize and output a pattern image and/or acontent image. For example, the display 310 may output an image renderedby the processor 340 of the electronic device 300. The processor 340 maygenerate a pattern image by rendering a calibration pattern usingparameters of the parallax optical element 320, and may generate acontent image by rendering content. The display 310 may output arendered pattern image and/or a rendered content image. Each of thepattern image and the content image may be an image in which images(e.g., a left image and a right image) corresponding to a plurality ofviewpoints are mixed. The display 310 may generate light correspondingto an output image through a backlight unit and/or self-light emission,and may transmit the light to the parallax optical element 320 that willbe described below. For example, the display 310 may be implemented asat least a portion of a HUD mounted on a vehicle, such as, for example,a motorcycle, an automobile, a train, a watercraft, an aircraft, and aspacecraft.

The parallax optical element 320 may provide light corresponding to theimage output from the display 310 to a plurality of viewpoints. Theparallax optical element 320 may be an optical element that is disposedon one surface (e.g., a front surface or a rear surface) of the display310 and that is configured to direct light corresponding to an imageoutput to the display 310 toward a plurality of viewpoints. For example,the parallax optical element 320 may direct light passing through aportion of the image output to the display 310 corresponding to a leftimage in an optical path to a left eye of a user. Similarly, theparallax optical element 320 may direct light passing through a portionof the image output to the display 310 corresponding to a right image inan optical path to a right eye of the user. The parallax optical element320 may include an optical layer, for example, a parallax barrier, alenticular lens array, or a directional backlight unit.

For example, the picture generator 214 of FIG. 2 may include the display310 and the parallax optical element 320. However, although the HUD 213is mainly an example to provide a stereoscopic image through awindshield in a vehicle as described in FIG. 2 , embodiments are notlimited thereto. The fold mirror 215 and the concave mirror 216 of theHUD 213 may magnify light corresponding to an image generated by adisplay 310 and the parallax optical element 320, and may provide thelight to a user, and an optical system for magnifying an image may alsochange according to an application. For example, a mirror may be omitteddepending on a design of a HUD, and mirrors may not be necessary in aflat panel display, for example, a television (TV). For convenience ofdescription, description of the above-described optical system (e.g., afold mirror and a concave mirror) for magnification of an image isomitted, and an optical path of light directed to an eye (e.g., a lefteye) of a user by the display 310 and the parallax optical element 320(e.g., a lenticular lens disposed in front of the display 310, or adirectional backlight unit disposed behind the display 310) disposed infront of or behind the display 310 will be described with reference toFIGS. 3 to 13 . For example, a lenticular lens may be laminated on onesurface of a display panel. However, embodiments are not limitedthereto, and optical elements (e.g., mirrors) configured to form avirtual image plane may be further included as necessary according to anapplication.

Through a combination of the display 310 and the parallax opticalelement 320 described above, the electronic device 300 may provide aleft image and a right image to the left eye and the right eye of theuser, respectively. The electronic device 300 may visualize content witha depth and provide the content as a stereoscopic graphic object to auser, by separating a graphic object with visualized content in a leftimage and a graphic object with visualized content in a right image fromeach other based on binocular disparity.

The input receiver 330 may receive an input of a user. For example, theinput receiver 330 may receive an input for calibration of the parallaxoptical element 320 from a user who observes a pattern image from areference viewpoint among a plurality of viewpoints. The input receiver330 may include, for example, at least one or a combination of two ormore of a touch panel, a touch screen, a dial, a jog dial, a shuttledial, a click wheel, a button, a slider bar, and a control lever. Thetouch panel may sense a touch input from a user. The touch screen maysense a touch input from a user while displaying a screen. The touchinput may be an input in which a contact is formed between an object(e.g., a finger and a pen) of a user and a touch panel and/or a touchscreen. The dial may sense a clockwise or counterclockwise rotationcontrol of a dial knob from a user. The shuttle dial may be a dial towhich an outer ring of a dial knob is rotatably coupled, and may sense aclockwise or counterclockwise rotation control of the outer ring. Thejog dial may be a dial in which an inner upper surface of the dial knobis rotatably coupled, and may sense a clockwise or counterclockwiserotation control of the inner upper surface. The click wheel may be aring-shaped touch sense interface and may detect whether a touch pointmoves while rotating in a clockwise direction or a counterclockwisedirection based on a central point of a ring shape. The button may sensea pressing control of a user, and may include, for example, an increase(e.g., “+”) button and a decrease (e.g., “−”) button. The slider bar maybe implemented as a physically slidable lever or a touch screen thatoutputs a slidable graphic object. The control lever may be switched inat least one direction, for example, switched upward or downward, orleftward or rightward.

According to example embodiments, a pattern image may be an imagerepresenting a pattern (hereinafter, referred to as a “calibrationpattern”) for calibration, and may indicate an image in which one ormore source images including the calibration pattern are rendered usingparameters of a parallax optical element. An example of the calibrationpattern and an example of the pattern image will be described below withreference to FIGS. 4 and 5 .

The processor 340 may output a pattern image generated by rendering thecalibration pattern toward a reference viewpoint. The processor 340 mayadjust at least one or a combination of two or more of a pitchparameter, a slanted angle parameter, and a position offset parameter ofthe parallax optical element 320 in response to an input. The processor340 may output the pattern image changed by re-rendering the calibrationpattern according to the adjusted parameter, through the display 310. Anoperation of the processor 340 is not limited to those described above,and will be further described with reference to FIGS. 4 to 14 . Eachparameter of the parallax optical element 320 will be described belowwith reference to FIG. 6 .

The memory 350 may temporarily or permanently store information used forcalibration. For example, the memory 350 may store instructions to beexecuted by the processor 340 to perform operations according to FIGS. 4to 14 that will be described below. The memory 350 may also storecalibrated parameters (e.g., a pitch parameter, a slanted angleparameter, and a position offset parameter).

An eye detector may detect a position of an eye (e.g., a left eye and/ora right eye) of a user. The electronic device 300 may provide an imageto a plurality of viewpoints through the display 310 and the parallaxoptical element 320, and may provide a pattern image for calibration toa reference viewpoint among the plurality of viewpoints. The electronicdevice 300 may detect a position of a reference eye (e.g., a left eye)between both eyes of a user through the above-described eye detector,and may determine a position corresponding to the reference eye as areference viewpoint. The eye detector may include a camera capable ofcapturing an interior of a vehicle in the example of FIG. 2 . The eyedetector may detect an eye position from an image that is acquired bycapturing the interior of the vehicle and that includes a user (e.g., adriver). However, embodiments are not limited thereto, and the processor340 of the electronic device 300 may receive an internal image capturedby an internal camera, and may detect and/or track a position of an eyeof a user from the received internal image.

FIG. 4 illustrates source images, a pattern image, and observed imagesfor calibration of a parallax optical element according to an exampleembodiment.

A calibration system 400 may include an electronic device 420. Theelectronic device 420 may include a parallax optical element 421 (e.g.,the parallax optical element 320 of FIG. 3 ) and a display panel 422(e.g., the display 310 of FIG. 3 ).

The electronic device 420 may generate a pattern image based on sourceimages. The source images may be stored in the electronic device 420 ormay be provided to the electronic device 420 by another device externalto the electronic device 420. The source images may each correspond to aviewpoint. For example, n source images may individually correspond to afirst viewpoint to an n-th viewpoint. In this example, n may be aninteger greater than or equal to 2. In the example embodiments, anexample in which n is set to 2 is mainly described, however, embodimentsare not limited thereto. When an image is provided to viewpointsrespectively corresponding to both eyes of a user, n may be 2. Theelectronic device 420 may generate a pattern image based on parametersso that an image corresponding to a reference viewpoint among aplurality of viewpoints corresponding to the source images may beobserved from the reference viewpoint, which will be further describedbelow. The reference viewpoint may be, for example, a viewpointcorresponding to a left eye of the user. The user may perform acalibration procedure while observing the pattern image only with theleft eye with his or her right eye shut during calibration.

The electronic device 420 may display the pattern image through thedisplay panel 422. The pattern image may be understood as a panel imagethat is generated based on source images including linear patterns andthat represents a calibration pattern. For example, calibration patternsmay be separately represented in the pattern image, and portionsobtained by dividing the pattern image by individual viewpoints may becombined through a parallax optical element so that the calibrationpatterns may be observed. In observed images 431 to 439 of FIG. 4 ,calibration patterns are shown as blurred horizontal lines with athickness, but embodiments are not limited thereto. For example, thecalibration patterns may be blurred vertical lines having a thickness. Acalibration pattern with a horizontal line or a calibration pattern witha vertical line may be used according to types of parameters, which willbe further described below.

A calibration pattern may be a pattern in which patterns (e.g., linearpatterns) included in one or more source images are combined. Forexample, the calibration pattern may be a pattern in which some ofpatterns of source images corresponding to viewpoints other than thereference viewpoint are combined based on a pattern of a source imagecorresponding to the reference viewpoint. The calibration pattern mayinclude the entire pattern of the source image corresponding to thereference viewpoint, and a portion of a pattern of a source imagecorresponding to a viewpoint (e.g., an (i−1)-th viewpoint and an(i+1)-th viewpoint) adjacent to the reference viewpoint (e.g., an i-thviewpoint). In the calibration pattern, a number of patterns of sourceimages corresponding to viewpoints (e.g., the first viewpoint and then-th viewpoint) distant from the reference viewpoint may be less than anumber of patterns of source images corresponding to viewpoints adjacentto the reference viewpoint. A human eye may clearly recognize an objectbased on a focus and recognize a blurred surrounding area, and acalibration pattern set based on an eyebox corresponding to the humaneye may be a pattern in which linear patterns of source imagescorresponding to respective viewpoints are combined by simulating theabove-described phenomenon. Accordingly, as described above, in theimages 431 to 439 observed from viewpoints, a linear patterncorresponding to the reference viewpoint may be relatively clearlyrepresented, and linear patterns corresponding to a neighboringviewpoint and a distant viewpoint may be relatively blurredlyrepresented.

The parallax optical element 421 may convert the pattern image into a 3Dimage using an autostereoscopic scheme. The parallax optical element 421may include an optical layer, for example, a parallax barrier, alenticular lens array, or a directional backlight unit. Although theparallax optical element 421, for example of a lenticular lens array anda parallax barrier, is located in front of the display panel 422, asshown in FIG. 4 , the parallax optical element 421 may also be locatedbehind the display panel 422, such as, for example, a directionalbacklight unit.

The parallax optical element 421 may assign directivity to light that isprovided to the display panel 422 or that is output from the displaypanel 422. Different images may be radiated to a plurality of viewpoints(e.g., viewpoints corresponding to both eyes of a viewer) throughdirectional light, and a viewer may feel a three-dimensional effect.When different images are not accurately radiated to both eyes of a userin the autostereoscopic scheme, crosstalk may occur in a 3D image. Forexample, when an error occurs between a design value and an actual valueof a parameter of the electronic device 420 during a production processor an installation process of the electronic device 420, crosstalk mayoccur.

For example, an image corresponding to a first pattern image generatedby rendering one or more source images including a first source imagemay be observed from a first viewpoint, and an image corresponding to ann-th pattern image generated by rendering one or more source imagesincluding an n-th source image may be observed from an n-th viewpoint.The image 431, that is, a first observed image may be an image observedwhen light corresponding to the first pattern image arrives at the firstviewpoint by passing through the parallax optical element 421. The image439, that is, an n-th observed image may be an image observed when lightcorresponding to the n-th pattern image arrives at the n-th viewpoint bypassing through the parallax optical element 421. A pattern imagecorresponding to one viewpoint (e.g., a reference viewpoint) may bedisplayed on portions of the display panel 422 through which lightdirected to the viewpoint passes. For example, in a pattern image, acalibration pattern may be divided and represented on portions of thedisplay panel 422 through which light directed to the referenceviewpoint passes. Light corresponding to portions obtained by dividingthe calibration pattern may be combined at the reference point whilepassing through the parallax optical element 421, and thus a user mayobserve the calibration pattern from the reference viewpoint.

According to an example embodiment, the electronic device 420 may detecta position of a reference eye of a user. For example, the electronicdevice 420 may detect a position of an eye of a user, through a separatecamera installed in the electronic device 420 or around and adjacent tothe electronic device 420. The electronic device 420 may performrendering so that the pattern image may be observed from a referenceviewpoint corresponding to the detected position of the eye.

FIG. 5 illustrates a source image and an observed image according to anexample embodiment.

First source images 510 and second source images 520 may correspond to aplurality of viewpoints, for example, a first viewpoint to an n-thviewpoint. Each of the first source images 510 may include a linearpattern with a horizontal line at a different position based on acorresponding viewpoint. Each of the second source images 520 mayinclude a linear pattern with a vertical line at a different positionbased on a corresponding viewpoint. The first source images 510 may beused to generate a first pattern image, and the second source images 520may be used to generate a second pattern image. In an example, anelectronic device may render one or more source images including a firstsource image corresponding to an i-th viewpoint for calibration at thei-th viewpoint, using parameters of a parallax optical element, togenerate a first pattern image corresponding to the i-th viewpoint. Inthis example, i denotes an integer greater than or equal to 1 and lessthan or equal to n. In another example, the electronic device may renderone or more source images including a second source image correspondingto the i-th viewpoint, using parameters of the parallax optical element,to generate a second pattern image corresponding to the i-th viewpoint.

For example, during calibration of an individual parameter among aplurality of parameters, a calibration pattern that facilitatesdetermination of whether a corresponding parameter is calibrated may bepresent. The first source images 510 may be black in areas other thanthe horizontal line. The second source images 520 may be black in areasother than the vertical line. The first source images 510 may be used tofacilitate calibration of a pitch parameter, and the second sourceimages 520 may be used to facilitate calibration of a slanted angleparameter. Among the source images, a linear pattern of a source imagecorresponding to a reference viewpoint may be changed to a color (e.g.,green) different from a color (e.g., white) of a linear pattern ofanother viewpoint.

The electronic device (e.g., the electronic device 300 of FIG. 3 ) maygenerate a pattern image through light field rendering so that a sourceimage corresponding to the reference viewpoint may be represented at thereference viewpoint. In FIG. 5 , an example in which the first viewpointis used as a reference viewpoint and a pattern image is rendered at thefirst viewpoint will be described. When it is assumed that the patternimage is output in a state in which parameter calibration is completed,a user may view a first observed image 519 and a second observed image529 from the reference viewpoint. For example, in an ideal environment,the first observed image 519 and the second observed image 529 may needto have the same pattern as a calibration pattern in which source imagesare combined corresponding to the reference viewpoint. However, in anactual environment where crosstalk is present, a gradation may befurther added to a calibration pattern corresponding to the referenceviewpoint or the calibration pattern may be further blurred in each ofthe first observed image 519 and the second observed image 529. Forreference, an example of rendering using parameters that are completelycalibrated is described above with reference to FIG. 5 . In the firstobserved image 519, a calibration pattern with a horizontal line (e.g.,a blurred horizontal line having a thickness) may be observed, and inthe second observed image 529, a calibration pattern with a verticalline (e.g., a blurred vertical line having a thickness) may be observed.Before calibration is completed, each linear calibration pattern may beobserved as an oblique linear pattern rather than a vertical line or ahorizontal line. Parameters for an alignment of the above-describedcalibration pattern will be described below with reference to FIG. 6 .

FIG. 6 illustrates parameters of a parallax optical element according toan example embodiment.

A first observed image 615 based on a first source image 610 may beviewed by a user, and a second observed image 625 based on a secondsource image 620 may be obtained. For example, unlike the example ofFIG. 5 in which crosstalk is present, the first observed image 615 andthe second observed image 625 are observed in a state in whichcalibration has been completed and an ideal environment in whichcrosstalk is absent, for convenience as shown in FIG. 6 .

A parameter of an electronic device (e.g., the electronic device 300 ofFIG. 3 ) may also be referred to as a parameter of a parallax opticalelement 651 (e.g., the parallax optical element 320 of FIG. 3 ).Parameters of the parallax optical element 651 may include a pitchparameter, a slanted angle parameter, and a position offset parameter.

The pitch parameter may be a parameter indicating a pitch p of a unitelement of the parallax optical element 651. The parallax opticalelement 651 may include unit elements. A unit element is a unit opticalelement that assigns a directivity to light corresponding to an imageoutput through a display 652, and may include, for example, a slit of aparallax barrier and a unit lens of lenticular lenses. The unit elementsmay be periodically arranged along one axis on a plane corresponding toan optical layer disposed on one surface of the display 652. The pitchparameter may indicate an interval of a periodic arrangement of unitelements. In FIG. 6 , the pitch parameter may indicate a horizontalperiod of the unit element. A length of an interval in which a view isiterated in a 3D image may be determined based on a pitch p. Using thepitch parameter, a gradient (e.g., a horizontal gradient) of a linearpattern in the first observed image 615 may be adjusted. For example,through adjustment of the pitch parameter, a linear calibration patterncorresponding to a pattern image may be rotated.

The slanted angle parameter may indicate a gradient of a unit element ofthe parallax optical element 651 relative to a reference axis of thedisplay 652. In FIG. 6 , the reference axis of the display 652 isillustrated as a vertical axis, and a slanted angle θ may indicate agradient of a unit element formed with respect to the vertical axis.Using the slanted angle parameter, a gradient of a linear pattern in thesecond observed image 625 may be adjusted.

The position offset parameter may indicate a relative position betweenthe parallax optical element 651 and the display 652. For example, theposition offset parameter may indicate a position offset s between astart position of a unit element and a start pixel of the display 652.In FIG. 6 , the position offset parameter is illustrated as a horizontaloffset between start positions of left unit elements based on a startpixel of an upper left end of the display 652. Using the position offsetparameter, the electronic device may adjust a vertical position of thelinear pattern in the first observed image 615 and a horizontal positionof the linear pattern in the second observed image 625.

According to an example embodiment, a processor of the electronic devicemay be configured to provide a user with at least one or a combinationof two or more of a first pattern image corresponding to a pitchparameter, a second pattern image corresponding to a slanted angleparameter, and a third pattern image corresponding to a position offsetparameter. The first pattern image may be generated based on firstsource images each including a horizontal line. The second pattern imagemay be generated based on second source images each including a verticalline. The third pattern image may be generated as a calibration patternincluding one of a vertical line and a horizontal line. As furtherdiscussed below, the pitch parameter may be calibrated independently ofother parameters based on a horizontal pattern. When the pitch parameteris calibrated, the slanted angle parameter may also be calibratedindependently of other parameters based on a vertical pattern. Theelectronic device may simultaneously provide two or more of the firstpattern image, the second pattern image, and the third pattern image, ormay sequentially provide the first pattern image, the second patternimage, and the third pattern image one by one.

According to various example embodiments, first calibration using thefirst pattern image and second calibration using the second patternimage may be sequentially performed. The electronic device may providethe second pattern image to the user when adjustment of the pitchparameter by providing the first pattern image is completed. Theelectronic device may provide the third pattern image to the user whenadjustment of the slanted angle parameter by providing the secondpattern image is completed. Since the adjustment of the pitch parameterhas an influence on the slanted angle parameter, the pitch parameter maybe adjusted before the adjustment of the slanted angle parameter.

In the first calibration, the user may observe the first pattern imagedisplayed by the electronic device, and may perform a calibration inputto adjust a first parameter set (e.g., a pitch parameter) of theelectronic device based on the observed first pattern image. In thefirst calibration, the providing of the first pattern image andadjustment of the first parameter set may be repeated untilcorresponding calibration is completed by the user. In the secondcalibration, the user may observe the second pattern image displayed bythe electronic device and may adjust a second parameter set (e.g., aslanted angle parameter) of the electronic device based on the observedsecond pattern image. In the second calibration, the providing of thesecond pattern image and adjustment of the second parameter set may berepeated until corresponding calibration is completed by the user.Similarly, third calibration for calibration of the position offsetparameter may be performed.

A process of calibration performed using a sequence of a horizontalpattern and a vertical pattern may be efficiently performed at a lowresolution in comparison to a calibration process using other complexpatterns such as a check pattern. This is because, since horizontalpattern-based calibration and vertical pattern-based calibration areperformed separately, complexity of a calibration task may be reduced.Autostereoscopic 3D image technology may be implemented in alow-resolution device such as a HUD. A HUD may have a relatively longviewing distance and a resolution that is insufficient for estimating aparameter using a single pattern image, in comparison to a generaldisplay device. Due to a catadioptric system included in the HUD,distortion may also occur in a 3D image. In an example, calibrations maybe sequentially performed using simple patterns, and thus such alow-resolution device or a device including an optical system mayexhibit high performance.

FIGS. 7, 8, and 9 illustrate examples of a change in a pattern imagebased on adjustment of parameters according to an example embodiment.

FIG. 7 illustrates a change in a pattern image according to adjustmentof a pitch parameter.

For example, when calibration of the pitch parameter is not completed, auser may observe a calibration pattern in which an angle is not alignedin each of images 711 and 712 observed by the user. For example, acalibration pattern of a source image may be a linear pattern (e.g., asingle horizontal line pattern having a thickness). A linear patternrepresented in each of the images 711 and 712 observed by the user maybe slightly slanted relative to a horizontal line and may have athickness.

An electronic device may induce the user to adjust the pitch parameterso that a corresponding linear pattern may be horizontally represented.For example, the electronic device may provide the user with acalibration pattern together with a reference line 790. A linear patternwith a thickness may include at least a portion of the reference line790. The reference line 790 may correspond to, for example, a horizontalline of a screen in FIG. 7 . Due to crosstalk, the reference line 790may be slightly curved. The reference line 790 may be partially coveredin the images 711 and 712 as shown in FIG. 7 , and accordingly the usermay observe only a portion of the reference line 790. In a calibratedimage 719, the entire reference line 790 may be represented.

According to an example embodiment, a processor may rotate a patterncorresponding to a first pattern image in a counterclockwise directionfrom a direction in which a user observes the pattern, in response to anincrease in a value of a pitch parameter among parameters of a parallaxoptical element according to an input. For example, the electronicdevice may change a value of the pitch parameter of the parallax opticalelement to a value greater than a preset value in response to an inputof the user, and may output a new first pattern image generated byre-rendering one or more source images including a first source imageusing the pitch parameter with the increased value. As shown in FIG. 7 ,when a set value of the pitch parameter increases, a pattern obtained byrotating a linear pattern of the image 711 corresponding to a previousfirst pattern image in the counterclockwise direction may be observed inthe calibrated image 719 corresponding to the new first pattern image.

In addition, the processor may rotate the pattern corresponding to thefirst pattern image in a clockwise direction from the direction the userobserves the pattern, in response to a decrease in the value of thepitch parameter among the parameters of the parallax optical elementaccording to an input. For example, the electronic device may change thevalue of the pitch parameter of the parallax optical element to a valueless than the pre-set value in response to an input of the user, and mayoutput a new first pattern image generated by re-rendering one or moresource images including the first source image using the pitch parameterwith the reduced value. As shown in FIG. 7 , when the set value of thepitch parameter decreases, a pattern obtained by rotating a linearpattern of the image 712 corresponding to a previous first pattern imagein the clockwise direction may be observed in the calibrated image 719corresponding to the new first pattern image.

For example, during rendering of view images (e.g., source images)corresponding to n (e.g., 17) viewpoints, the electronic device mayvisualize a linear pattern of a view image (e.g., an eighth view image)corresponding to an i-th viewpoint that is a reference viewpoint, with areference color (e.g., green). The reference color may be a colordistinguishable from a color of a linear pattern of another sourceimage. The calibration pattern may be a pattern observed from oneviewpoint (e.g., a reference viewpoint) in partial images obtained bydividing a panel image (e.g., a pattern image), which is generated byrendering view images corresponding to all the n viewpoints and which isoutput, into n equal portions. In the calibration pattern, the referenceline 790 may represent a linear pattern of an intermediate view image(e.g., a view image corresponding to an eighth viewpoint in a centralposition among 17 viewpoints) among view images reaching a human eye atthe reference viewpoint.

The reference line 790 may be fixed without rotation even though thecalibration pattern is rotated, and covered portions of the referenceline 790 may appear according to rotation of the calibration pattern.Through the above-described rotation of the calibration pattern, acovered portion of the reference line 790 may appear, and accordinglythe calibration pattern may be aligned with the reference line 790. Theprocessor may continue to receive a calibration input from the useruntil the calibration pattern (e.g., a linear pattern) is aligned withthe reference line 790. For example, the user may adjust the pitchparameter so that the linear pattern may be parallel to the referenceline 790 (e.g., a horizontal line). When a first calibration end inputis received from the user, the processor may determine that thecalibration of the pitch parameter is completed. For example, whetherthe calibration pattern and the reference line 790 are aligned may bedetermined by the user. However, the reference line 790 may not benecessarily presented, and the electronic device may be designed toreceive, from the user, an input for adjustment of the pitch parameterto allow the linear pattern of the calibration pattern observed by theuser to be horizontal during the calibration of the pitch parameter. Forexample, the user may adjust a calibration pattern corresponding to thefirst pattern image to be horizontal through visual estimation.

FIG. 8 illustrates a change in a pattern image according to adjustmentof a slanted angle parameter.

For example, when calibration of the slanted angle parameter is notcompleted, a user may observe a calibration pattern in which an angle isnot aligned in each of images 821 and 822 observed by the user. Forexample, a pattern of a source image may be a linear pattern (e.g., asingle vertical line pattern having a thickness). A linear patternrepresented in each of the images 821 and 822 observed by the user maybe slightly slanted related to a vertical line and may have a thickness.

An electronic device may induce the user to adjust the slanted angleparameter so that a corresponding linear pattern may be verticallyrepresented. For example, the electronic device may provide acalibration pattern including a reference line 890 to the user. A linearpattern with a thickness may include at least a portion of the referenceline 890. The reference line 890 may correspond to, for example, avertical line of a screen in FIG. 8 . The reference line 890 may bepartially covered in the images 821 and 822 as shown in FIG. 8 , andaccordingly the user may observe only a portion of the reference line890. In a calibrated image 819, the entire reference line 890 may berepresented.

According to an example embodiment, a processor may rotate a patterncorresponding to a second pattern image in a clockwise direction from adirection in which the user observes the pattern, in response to anincrease in a value of the slanted angle parameter among parameters of aparallax optical element according to an input. For example, theelectronic device may change the value of the slanted angle parameter ofthe parallax optical element to a value greater than a pre-set value inresponse to an input of the user, and may output a new second patternimage generated by re-rendering one or more source images including asecond source image using the slanted angle parameter with the increasedvalue. As shown in FIG. 8 , when a set value of the slanted angleparameter increases, a pattern obtained by rotating a linear pattern ofthe image 821 corresponding to a previous second pattern image in theclockwise direction may be observed in a calibrated image 829corresponding to the new second pattern image.

In addition, the processor may rotate the pattern corresponding to thesecond pattern image in a counterclockwise direction from the directionin which the user observes the pattern, in response to a decrease in thevalue of the slanted angle parameter among the parameters of theparallax optical element according to the input. For example, theelectronic device may change the value of the slanted angle parameter ofthe parallax optical element to a value less than the pre-set value inresponse to an input of the user, and may output a new second patternimage generated by re-rendering one or more source images including thesecond source image using the slanted angle parameter with the reducedvalue. As shown in FIG. 8 , when the set value of the slanted angleparameter decreases, a pattern obtained by rotating a linear pattern ofthe image 822 corresponding to a previous second pattern image in thecounterclockwise direction may be observed in the calibrated image 829corresponding to the new second pattern image.

The user may adjust the slanted angle parameter so that the linearpattern may be parallel to the reference line 890 (e.g., a verticalline). When a second calibration end input is received from the user,the processor may determine that the calibration of the slanted angleparameter is completed. For example, whether the calibration pattern andthe reference line 890 are aligned may be determined by the user.However, the reference line 890 may not be necessarily presented, andthe electronic device may be designed to receive, from the user, aninput for adjustment of the slanted angle parameter to allow the linearpattern of the calibration pattern observed by the user to be verticalduring the calibration of the slanted angle parameter. For example, theuser may adjust a calibration pattern corresponding to the secondpattern image to be vertical through visual estimation.

FIG. 9 illustrates a change in a pattern image according to adjustmentof a position offset parameter.

For example, if calibration of the position offset parameter is notcompleted, a user may observe a calibration pattern in which a positionis not aligned in each of images 921 a, 922 a, 921 b, and 922 b observedby the user. For example, a calibration pattern combined for a referenceviewpoint may be a linear pattern (e.g., a single horizontal linepattern or a single vertical line pattern). For example, a third patternimage for the calibration of the position offset parameter may berendered using one or more first source images or may be rendered usingone or more second source images. When one of a vertical pattern and ahorizontal pattern is aligned with the center, the other of the verticalpattern and the horizontal pattern may also be aligned with the center,and accordingly the position offset parameter may be adjusted using oneof the vertical pattern and the horizontal pattern. For reference, theposition offset parameter may not have an influence on a gradient of thelinear pattern. The position offset parameter may be adjustedindependently of the pitch parameter and the slanted angle parameter.

According to an example embodiment, a processor may move a patterncorresponding to the third pattern image in one direction from adirection in which the user observes the pattern, in response to anincrease in a value of the position offset parameter among parameters ofthe parallax optical element according to an input. In an example, whenthe pattern corresponding to the third pattern image is a horizontalpattern and when the value of the position offset parameter increases,an electronic device may provide a calibrated image 929 a by moving apattern of the image 921 a in a first direction (e.g., a downwarddirection). In another example, when the pattern corresponding to thethird pattern image is a vertical pattern and when the value of theposition offset parameter increases, the electronic device may provide acalibrated image 929 b by moving a pattern of the image 921 b in a thirddirection (e.g., a direction from the right to the left).

In addition, the processor may move the pattern corresponding to thethird pattern image in an opposite direction to the one direction fromthe direction in which the user observes the pattern, in response to adecrease in the value of the position offset parameter among theparameters of the parallax optical element according to an input. In anexample, when the pattern corresponding to the third pattern image is ahorizontal pattern and when the value of the position offset parameterdecreases, the electronic device may provide the calibrated image 929 aby moving a pattern of the image 922 a in a second direction (e.g., anupward direction) opposite to the first direction. In another example,when the pattern corresponding to the third pattern image is a verticalpattern and when the value of the position offset parameter decreases,the electronic device may provide the calibrated image 929 b by moving apattern of the image 922 b in a fourth direction (e.g., a direction fromthe left to the right) opposite to the second direction.

Through the above-described adjustment of the position offset parameter,the electronic device may change the position of the calibration patternso that reference lines 991 and 992 may be located at a central portionof the calibration pattern. The user may adjust a calibration patterncorresponding to the third pattern image to be located in a centralportion (e.g., a position corresponding to a reference line) of a range(e.g., a field of view) in which the calibration pattern correspondingto the third pattern image is observed, through visual estimation.

FIG. 10 illustrates parameter adjustment using a slider bar according toan example embodiment.

According to an example embodiment, an electronic device may output anddisplay a slider bar interface 1020 through a touch screen. Theelectronic device may receive a touch control to move a slider barobject on the touch screen from a user 1090. In an example, when theslider bar object moves in one direction (e.g., a direction from left toright) in response to an input of the user 1090, the electronic devicemay increase a value of a parameter. In another example, when the sliderbar object moves in another direction (e.g., a direction from right toleft) in response to an input of the user 1090, the electronic devicemay reduce the value of the parameter. In FIG. 10 , an example ofcalibration of a pitch parameter is illustrated. The electronic devicemay increase a value of the pitch parameter when the slider bar objectis moved in one direction. For example, when a movement of the sliderbar object in one direction is detected, the electronic device mayprovide a calibrated image 1019 to the user 1090 by rotating a patternof an observed image 1011 in a counterclockwise direction.

FIG. 11 illustrates parameter adjustment using a touch interfaceaccording to an example embodiment.

According to an example embodiment, a processor may map adjustment of atleast one of a pitch parameter and a slanted angle parameter to an inputmodule capable of detecting a rotation control 1129 in an inputreceiver. For example, the input receiver may detect the rotationcontrol 1129 from a user. The input receiver may include a plurality ofinput modules or devices, and an electronic device may select an inputmodule configured to detect the rotation control 1129 from the pluralityof input modules. When the rotation control 1129 by the user is detectedby the input receiver during calibration of the parallax opticalelement, the processor may adjust at least one of a pitch parameter anda slanted angle parameter among parameters of a parallax opticalelement. The electronic device may adjust the pitch parameter and/or theslanted angle parameter through a touch interface (e.g., a touch paneland a touch screen 1120) and/or a physical control interface (e.g., arotary dial) configured to detect the rotation control 1129. In FIG. 11, an example of detecting the rotation control 1129 through the touchscreen 1120 is illustrated.

The input receiver may include the touch screen 1120. The processor mayoutput and display on the touch screen 1120, a first graphicrepresentation 1125 for guiding the rotation control 1129 duringcalibration of at least one of the pitch parameter and the slanted angleparameter. For example, in FIG. 11 , the electronic device may output acircular first graphic representation 1125 that guides the rotationcontrol 1129 to the touch screen 1120. When a movement of a touch pointalong at least partially circular trajectory from a point on the touchscreen 1120 is detected corresponding to the first graphicrepresentation 1125, the processor may adjust at least one of the pitchparameter and the slanted angle parameter.

For example, when the touch point moves along a circular trajectory in aclockwise direction from a central point of the circular trajectory, theelectronic device may rotate an observed calibration pattern 1110 in theclockwise direction. When the touch point is rotated in the clockwisedirection during calibration of the pitch parameter, the electronicdevice may reduce a value of the pitch parameter. When the touch pointis rotated in the clockwise direction during calibration of the slantedangle parameter, the electronic device may increase a value of theslanted angle parameter. When the touch point moves in acounterclockwise direction, the electronic device may increase the valueof the pitch parameter and/or reduce the value of the slanted angleparameter.

However, embodiments are not limited to supporting detection of therotation control 1129 in the touch interface. The processor may mapadjustment of the position offset parameter to an input module or devicecapable of detecting a linear control in the input receiver. The inputreceiver may include a plurality of input modules, and the electronicdevice may select an input module capable of detecting a linear control(e.g., a linear manipulation) from the plurality of input modules. Forexample, the processor may output, to the touch screen 1120, a secondgraphic representation for guiding a linear control during calibrationof the position offset parameter. The processor may output the sliderbar interface 1020 of FIG. 10 as a second graphic representation throughthe touch screen 1120 during calibration of the position offsetparameter. When a linear movement of the touch point from one point onthe touch screen 1120 to another point is detected corresponding to thesecond graphic representation, the processor may adjust the positionoffset parameter. For example, the processor may increase a value of theposition offset parameter when the second graphic representation ismoved in one direction, and may reduce the value of the position offsetparameter when the second graphic representation is moved in anotherdirection. When a movement of the second graphic representation in onedirection is detected, the electronic device may linearly move thecalibration pattern 1110 in the one direction. Similarly, when amovement of the second graphic representation in another direction isdetected, the electronic device may linearly move the calibrationpattern 1110 in the other direction.

Although the rotation control and the linear control in the touchinterface have been described above with reference to FIG. 11 ,embodiments are not limited thereto. An example of mapping between aphysical control interface and parameter adjustment will be describedbelow with reference to FIG. 12 .

FIG. 12 illustrates parameter adjustment using a dial interfaceaccording to an example embodiment.

According to an example embodiment, an input receiver of an electronicdevice may include a dial interface 1221. The dial interface 1221 mayinclude a dial knob that is coupled to the electronic device to berotated in a clockwise direction or a counterclockwise direction. Inaddition, the dial knob may be coupled to the electronic device to movealong one axis. For example, the dial interface 1221 may detect both arotation control and a linear control.

In an example, when a counterclockwise rotation control is detected bythe input receiver while a first pattern image corresponding to a pitchparameter is being provided, a processor may rotate a calibrationpattern 1210 corresponding to the first pattern image in acounterclockwise direction. When the counterclockwise rotation controlis detected by the input receiver while the first pattern imagecorresponding to the pitch parameter is being provided, the processormay increase a value of the pitch parameter. When a counterclockwiserotation of the dial knob in the dial interface 1221 is detected, theelectronic device may rotate the calibration pattern 1210 in thecounterclockwise direction by increasing the value of the pitchparameter as described above.

In another example, when a clockwise rotation control is detected by theinput receiver while the first pattern image corresponding to the pitchparameter is being provided, the processor may rotate the calibrationpattern 1210 corresponding to the first pattern image in a clockwisedirection. When the clockwise rotation control is detected by the inputreceiver while the first pattern image corresponding to the pitchparameter is being provided, the processor may reduce the value of thepitch parameter. When a clockwise rotation of the dial knob in the dialinterface 1221 is detected, the electronic device may rotate thecalibration pattern 1210 in the clockwise direction by reducing thevalue of the pitch parameter as described above.

Thus, the electronic device may match a rotation control direction(e.g., a rotation direction of the dial knob) to a rotation direction ofthe calibration pattern 1210 during adjustment of the pitch parameter.The electronic device may provide a more intuitive and user-friendlycalibration control to a user. For example, if an error occurs in aparameter due to an internal factor or an external factor, a user whoowns a vehicle may more easily and manually calibrate a parameter of aparallax optical element through the above-described control. Thus, theuser may minimize an external service support for calibration of theparameter of the parallax optical element.

In an example, when a clockwise rotation control is detected by theinput receiver while a second pattern image corresponding to a slantedangle parameter is being provided, the processor may rotate acalibration pattern 1210 corresponding to the second pattern image inthe clockwise direction. When the clockwise rotation control is detectedby the input receiver while the second pattern image corresponding tothe slanted angle parameter is being provided, the processor mayincrease a value of the slanted angle parameter. When a clockwiserotation of the dial knob in the dial receiver 1221 is detected duringcalibration of the slanted angle parameter, the electronic device mayrotate the calibration pattern 1210 in the clockwise direction byincreasing the value of the slanted angle parameter as described above.

In another example, when a counterclockwise rotation control is detectedby the input receiver while the second pattern image corresponding tothe slanted angle parameter is being provided, the processor may rotatethe calibration pattern 1210 corresponding to the second pattern imagein the counterclockwise direction. When the counterclockwise rotationcontrol is detected by the input receiver while the second pattern imagecorresponding to the slanted angle parameter is being provided, theprocessor may reduce the value of the slanted angle parameter. When acounterclockwise rotation of the dial knob in the dial receiver 1221 isdetected during the calibration of the slanted angle parameter, theelectronic device may rotate the calibration pattern 1210 in thecounterclockwise direction by reducing the value of the slanted angleparameter as described above.

Thus, the electronic device may match a rotation control direction(e.g., a rotation direction of the dial knob) to a rotation direction ofthe calibration pattern 1210 during adjustment of the slanted angleparameter. The electronic device may provide a more intuitivecalibration control to a user. For example, an increase and a decreasein the value of the slanted angle parameter according to the rotationcontrol direction in adjustment of the slanted angle parameter, and anincrease and a decrease in the value of the pitch parameter according tothe rotation control direction in adjustment of the pitch parameter maybe opposite to each other. For example, in response to a clockwisecontrol, the value of the pitch parameter may decrease and the value ofthe slanted angle parameter may increase. In response to acounterclockwise control, the value of the pitch parameter may increaseand the value of the slanted angle parameter may decrease.

In an example, when a linear control in one direction is detected by theinput receiver while a third pattern image corresponding to a positionoffset parameter is being provided, the processor may move a calibrationpattern 1210 corresponding to third first pattern image in the onedirection. When the linear control in the one direction is detected bythe input receiver while the third pattern image corresponding to theposition offset parameter is being provided, the processor may increasea value of the position offset parameter. When a movement of the dialknob in the dial receiver 1221 in one direction (e.g., a direction froma front side to a rear side) is detected, the electronic device may movethe calibration pattern 1210 in a corresponding direction (e.g., adirection from top to bottom) by increasing the value of the positionoffset parameter.

In another example, when a linear control in an opposite direction tothe one direction is detected by the input receiver while the thirdpattern image corresponding to the position offset parameter is beingprovided, the processor may move the calibration pattern 1210corresponding to the third pattern image in the opposite direction tothe one direction. When the linear control in the opposite direction tothe one direction is detected by the input receiver while the thirdpattern image corresponding to the position offset parameter is beingprovided, the processor may reduce the value of the position offsetparameter. When a movement of the dial knob in the dial receiver 1221 inanother direction (e.g., a direction from the rear side to the frontside) is detected, the electronic device may move the calibrationpattern 1210 in a direction (e.g., a direction from bottom to top)corresponding to the other direction by reducing the value of theposition offset parameter.

Thus, the electronic device may match a linear control direction (e.g.,a movement direction of the dial knob) to a linear movement direction ofthe calibration pattern 1210 when the position offset parameter isadjusted. Thus, the electronic device may provide a more intuitivecalibration control to a user.

Although the dial interface 1221 including the dial knob has been mainlydescribed with reference to FIG. 12 , embodiments are not limitedthereto. The electronic device may receive an input for calibrationthrough a button 1223 attached to a steering wheel of a vehicle, andvarious levers and/or buttons 1222 and 1224 disposed on a center fascia.

FIG. 13 illustrates a calibration result according to an exampleembodiment.

Before calibration of a parallax optical element is completed, a lefteye image and a right eye image may include a portion of content of theright eye image and a portion of content of the left eye image,respectively, as indicated by reference numeral 1310. According to anexample embodiment, when the calibration of the parallax optical elementis completed, the content of the left eye image and the content of theright eye image may be displayed separately from each other, asindicated by reference numeral 1320. For example, crosstalk may beeliminated.

According to an example embodiment, when a calibration completion inputis received from a user, a processor may store parameters of theparallax optical element that are personalized to the user. Anelectronic device may render a content image using the personalizedparameters and output the content image to a display. Through feedbackof an interface and a calibration pattern as described above in FIGS. 4to 12 , a user may intuitively and manually adjust the parameters of theparallax optical element with convenience.

FIG. 14 is a flowchart illustrating a calibration method according to anexample embodiment.

In operation 1410, an electronic device may provide light correspondingto a pattern image, which is generated by rendering a calibrationpattern and output from a display, to a reference viewpoint, using aparallax optical element

In operation 1420, the electronic device may receive an input forcalibration of parameters of the parallax optical element from a userwho observes the pattern image from the reference viewpoint.

In operation 1430, the electronic device may adjust at least one or acombination of two or more of a pitch parameter, a slanted angleparameter, and a position offset parameter of the parallax opticalelement, in response to the input.

In operation 1440, the electronic device may output the pattern imagechanged by re-rendering the calibration pattern according to an adjustedparameter, through the display.

However, operations of the electronic device are not limited to thosedescribed with reference to FIG. 14 and may be performed along with atleast one of the operations described above with reference to FIGS. 1 to13 in time-series manner or in parallel.

The examples described herein may be implemented using a hardwarecomponent, a software component and/or a combination thereof. Aprocessing device may be implemented using one or more general-purposeor special-purpose computers, such as, for example, a processor, acontroller and an arithmetic logic unit (ALU), a digital signalprocessor (DSP), a microcomputer, an FPGA, a programmable logic unit(PLU), a microprocessor or any other device capable of responding to andexecuting instructions in a defined manner. The processing device mayrun an operating system (OS) and one or more software applications thatrun on the OS. The processing device also may access, store, manipulate,process, and create data in response to execution of the software. Forpurpose of simplicity, the description of a processing device is used assingular; however, one skilled in the art will appreciate that aprocessing device may include multiple processing elements and multipletypes of processing elements. For example, the processing device mayinclude a plurality of processors, or a single processor and a singlecontroller. In addition, different processing configurations arepossible, such as parallel processors.

The software may include a computer program, a piece of code, aninstruction, or some combination thereof, to independently or uniformlyinstruct or configure the processing device to operate as desired.Software and data may be embodied permanently or temporarily in any typeof machine, component, physical or virtual equipment, computer storagemedium or device, or in a propagated signal wave capable of providinginstructions or data to or being interpreted by the processing device.The software also may be distributed over network-coupled computersystems so that the software is stored and executed in a distributedfashion. The software and data may be stored by one or morenon-transitory computer-readable recording mediums.

The methods according to the above-described example embodiments may berecorded in non-transitory computer-readable media including programinstructions to implement various operations of the above-describedexample embodiments. The media may also include, alone or in combinationwith the program instructions, data files, data structures, and thelike. The program instructions recorded on the media may be thosespecially designed and constructed for the purposes of exampleembodiments, or they may be of the kind well-known and available tothose having skill in the computer software arts. Examples ofnon-transitory computer-readable media include magnetic media such ashard disks, floppy disks, and magnetic tape; optical media such asCD-ROM discs, DVDs, and/or Blue-ray discs; magneto-optical media such asoptical discs; and hardware devices that are specially configured tostore and perform program instructions, such as read-only memory (ROM),random access memory (RAM), flash memory (e.g., USB flash drives, memorycards, memory sticks, etc.), and the like. Examples of programinstructions include both machine code, such as produced by a compiler,and files containing higher-level code that may be executed by thecomputer using an interpreter.

The above-described devices may be configured to act as one or moresoftware modules in order to perform the operations of theabove-described examples, or vice versa.

A number of examples have been described above. Nevertheless, it shouldbe understood that various modifications may be made to these examples.For example, suitable results may be achieved if the describedtechniques are performed in a different order and/or if components in adescribed system, architecture, device, or circuit are combined in adifferent manner and/or replaced or supplemented by other components ortheir equivalents.

Therefore, the scope of the disclosure is defined not by the detaileddescription, but by the claims and their equivalents, and all variationswithin the scope of the claims and their equivalents are to be construedas being included in the disclosure.

What is claimed is:
 1. An electronic device comprising: a display tooutput an image; a parallax optical element configured to provide lightcorresponding to the image to a plurality of viewpoints; an inputinterface configured to receive a first input, a second input, and athird input to calibrate the parallax optical element from a user whoobserves a pattern image from a reference viewpoint among the pluralityof viewpoints; and a processor configured to: output the pattern imagegenerated by rendering a calibration pattern toward the referenceviewpoint; adjust a pitch parameter based on the first input, a slantedangle parameter based on the second input, and a position offsetparameter of the parallax optical element based on the third input; andoutput the pattern image adjusted by re-rendering the calibrationpattern based on an adjusted parameter.
 2. The electronic device ofclaim 1, wherein the processor is further configured to: rotate apattern corresponding to a first pattern image in a counterclockwisedirection from a direction in which the user observes the pattern, basedon an increase in a value of the pitch parameter among parameters of theparallax optical element based on the first input; and rotate thepattern corresponding to the first pattern image in a clockwisedirection from the direction in which the user observes the pattern,based on a decrease in the value of the pitch parameter among theparameters of the parallax optical element based on the first input. 3.The electronic device of claim 1, wherein the processor is furtherconfigured to: rotate a pattern corresponding to a second pattern imagein a clockwise direction from a direction in which the user observes thepattern, based on an increase in a value of the slanted angle parameteramong parameters of the parallax optical element based on the secondinput; and rotate the pattern corresponding to the second pattern imagein a counterclockwise direction from the direction in which the userobserves the pattern, based on a decrease in the value of the slantedangle parameter among the parameters of the parallax optical elementbased on the second input.
 4. The electronic device of claim 1, whereinthe processor is further configured to: move a pattern corresponding toa third pattern image in one direction from a direction in which theuser observes the pattern, based on an increase in a value of theposition offset parameter among parameters of the parallax opticalelement based on the third input; and move the pattern corresponding tothe third pattern image in an opposite direction to the one directionfrom the direction in which the user observes the pattern, based on adecrease in the value of the position offset parameter among theparameters of the parallax optical element based on the third input. 5.The electronic device of claim 1, wherein the input interface comprisesat least one of a touch panel, a touch screen, a dial, a jog dial, ashuttle dial, a click wheel, a button, a slider bar, and a controllever.
 6. The electronic device of claim 1, wherein the processor isfurther configured to: map adjustment of at least one of the pitchparameter and the slanted angle parameter to an input device configuredto detect a rotation control in the input interface; and map adjustmentof the position offset parameter to the input device further configuredto detect a linear control in the input interface.
 7. The electronicdevice of claim 1, wherein the input interface is configured to detect arotation control input by the user, and wherein the processor is furtherconfigured to adjust at least one of the pitch parameter and the slantedangle parameter among parameters of the parallax optical element, basedon the rotation control input by the user being detected by the inputinterface during calibration of the parallax optical element.
 8. Theelectronic device of claim 1, wherein the processor is furtherconfigured to: rotate a first calibration pattern corresponding to afirst pattern image corresponding to the pitch parameter in acounterclockwise direction, based on a counterclockwise rotation controlbeing detected by the input interface while the first pattern image isbeing provided; and rotate the first calibration pattern correspondingto the first pattern image in a clockwise direction, based on aclockwise rotation control being detected by the input interface whilethe first pattern image is being provided.
 9. The electronic device ofclaim 8, wherein the processor is further configured to: increase avalue of the pitch parameter, based on the counterclockwise rotationcontrol being detected by the input interface while the first patternimage is being provided; and reduce the value of the pitch parameter,based on the clockwise rotation control being detected by the inputinterface while the first pattern image is being provided.
 10. Theelectronic device of claim 1, wherein the processor is furtherconfigured to: rotate a second calibration pattern corresponding to asecond pattern image corresponding to the slanted angle parameter in aclockwise direction, based on a clockwise rotation control beingdetected by the input interface while the second pattern image is beingprovided; and rotate the second calibration pattern corresponding to thesecond pattern image in a counterclockwise direction, based on acounterclockwise rotation control being detected by the input interfacewhile the second pattern image is being provided.
 11. The electronicdevice of claim 10, wherein the processor is further configured to:increase a value of the slanted angle parameter, based on the clockwiserotation control being detected by the input interface while the secondpattern image is being provided; and reduce the value of the slantedangle parameter, based on the counterclockwise rotation control beingdetected by the input interface while the second pattern image is beingprovided.
 12. The electronic device of claim 1, wherein the processor isfurther configured to: move a third calibration pattern corresponding toa third pattern image corresponding to the position offset parameter ina first direction, based on a linear control in the first directionbeing detected by the input interface while the third pattern image isbeing provided; and move the third calibration pattern corresponding tothe third pattern image in a second direction that is opposite to thefirst direction, based on a linear control in the second direction tothe first direction being detected by the input interface while thethird pattern image is being provided.
 13. The electronic device ofclaim 1, wherein the processor is further configured to: increase avalue of the position offset parameter, based on a linear control in afirst direction being detected by the input interface while a thirdpattern image corresponding to the position offset parameter is beingprovided; and reduce the value of the position offset parameter based ona linear control in a second direction opposite to the first directionbeing detected by the input interface while the third pattern image isbeing provided.
 14. The electronic device of claim 1, wherein the inputinterface comprises a touch screen, and the processor is furtherconfigured to: output, via the touch screen, a first graphicrepresentation configured to guide a rotation control during calibrationof at least one of the pitch parameter and the slanted angle parameter;adjust at least one of the pitch parameter and the slanted angleparameter, based on a movement of a touch point along at least partiallycircular trajectory from a point on the touch screen being detectedcorresponding to the first graphic representation; output, via the touchscreen, a second graphic representation configured to guide a linearcontrol during calibration of the position offset parameter; and adjustthe position offset parameter, based on a linear movement of a touchpoint from one point on the touch screen to another point being detectedcorresponding to the second graphic representation.
 15. The electronicdevice of claim 1, wherein the processor is further configured to: storeparameters of the parallax optical element that are personalized to theuser, based on a calibration completion input being received from theuser; and render a content image based on the personalized parametersand output, via the display, the content image.
 16. The electronicdevice of claim 1, wherein the processor is further configured toprovide the user with at least one of a first pattern imagecorresponding to the pitch parameter, a second pattern imagecorresponding to the slanted angle parameter, and a third pattern imagecorresponding to the position offset parameter.
 17. The electronicdevice of claim 16, wherein the processor is further configured to:provide the second pattern image to the user, based on adjustment of thepitch parameter by providing the first pattern image being completed;and provide the third pattern image to the user, based on adjustment ofthe slanted angle parameter by providing the second pattern image beingcompleted.
 18. The electronic device of claim 1, wherein the display isincluded in a head-up display (HUD) mounted on a vehicle, and whereinthe vehicle is one of a motorcycle, an automobile, a train, awatercraft, an aircraft, and a spacecraft.
 19. A method implemented by aprocessor, the method comprising: providing light corresponding to apattern image to a reference viewpoint through a parallax opticalelement, the pattern image being generated by rendering a calibrationpattern and output from a display; receiving a first input, a secondinput, and a third input to calibrate parameters of the parallax opticalelement from a user who observes the pattern image from the referenceviewpoint; adjusting at least one of a pitch parameter based on thefirst input, a slanted angle parameter based on the second input, and aposition offset parameter of the parallax optical element based on thethird input; and outputting the pattern image adjusted by re-renderingthe calibration pattern based on an adjusted parameter, by the display.20. A non-transitory computer-readable storage medium storinginstructions that, when executed by the processor, cause the processorto perform the method of claim 19.